Hello,
I plan on growing vegetables in a raised garden bed this year and I am hoping you can tell me if it’s safe to use perlite in the soil. Is there a good substitute for perlite?
Thank you.
Thank you for contacting the Toronto Master Gardeners about a raised bed vegetable garden.
The addition of perlite into your outdoor raised bed vegetable garden is not recommended. Perlite is one component of potting soil used in containers or pots. Potting soil is made up of many different products that stop the medium from compacting and encourage good drainage and aeration.
Please take a look at the following answer from one of our archived posts for information on the specific soil materials and requirements for a raised bed vegetable garden:
Good soil quality is important for the intensive planting that you plan to do. The soil requirements may be different for existing beds vs. new beds. In general, the soil should contain at least 1/3 compost. This helps with soil structure and thus water retention / drainage and soil tilth (physical condition of the soil). Some experts suggest 3/4 triple mix (a combination of peat moss, compost and top soil) and 1/3 compost. Soil additions for your existing vegetable beds depends on the current soil conditions. Regular additions of compost before, during and after the growing season will help to maintain the soil conditions and nutrients you need for intensive growing practices. Some “heavy feeding” vegetables such as tomatoes may benefit from application of organic fertilizer. Well rotted / composted manure can be mixed into soil where nitrogen-loving vegetables (e.g., cabbage, broccoli) are to be grown. Avoid excessive nitrogen for root vegetables and legumes. The following references may be helpful to you.
https://savvygardening.com/the-best-soil-for-a-raised-garden-bed/
https://extension.umd.edu/hgic/topics/soil-fill-raised-beds
https://squarefootgardening.org/2019/05/do-you-have-to-replace-mels-mix/
Good luck with your raised vegetable garden.